Question

If ${V_c}$ is the speed of light in vacuum and ${V_m}$ the speed of light in a given medium,
the refractive index of the medium is:
(A). \[\dfrac{{{V}_{m}}}{{{V}_{C}}}\]
(B). \[\dfrac{{{V}_{C}}}{{{V}_{M}}}\]
(C). \[{{V}_{m}}\times {{V}_{c}}\]
(D). \[{{V}_{m}}+{{V}_{c}}\]

Answer 1

Hint: In optics, the refractive index (otherwise called refraction index or index of refraction) of a material is a dimensionless number that depicts how quick light goes through the material. It is characterized as:
\[n=\dfrac{c}{v}\]

Complete step by step answer:
The correct answer is B.
\[n=\dfrac{{{V}_{c}}}{{{V}_{m}}}\]
where c is known as the speed of light in vacuum and v is the stage velocity of light in the medium. For instance, the refractive index of water is 1.333, implying that light ventures 1.333 occasions as quick in vacuum as in water. Expanding refractive index relates to diminishing speed of light in the material.
The refractive index decides how much the way of light is bowed, or refracted, when entering a material. This is portrayed by Snell's law of refraction \[n_1\text{ }sin{\theta}_1\text{ }=\text{ }n_2\text{ }sin{\theta}_2\], where ${\theta}_1$ and ${\theta}_2$ are the edges of occurrence and refraction, separately, of a beam crossing the interface between two media with refractive lists $n_1$ and $n_2$.
The refractive files additionally decide the measure of light that is reflected when arriving at the interface, just as the basic plot for all out inside reflection, their power (Fresnel's equations) and Brewster's angle.

Note: The refractive index changes with wavelength, this makes white light split into constituent hues when refracted. This is called scattering. It very well may be seen in crystals and rainbows, and as chromatic variation in focal points.
Light proliferation in engrossing materials can be depicted utilizing a complex-esteemed refractive index. The nonexistent part at that point handles the constriction, while the genuine part represents refraction. For most of the materials the refractive index changes with wavelength by a few percent over the noticeable range.